Calice

Calice is an RPG where leveling up your hero means leveling up your real English. Every battle is a speaking, writing, reading or listening challenge — no flashcards, no multiple choice.

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Inspiration

Calice was born from our own experience learning English.

One of our partners started studying at an English academy. The academy teaches the fundamentals and then sends you home to review on your own, but the websites and apps built for that are just exercises: static, repetitive, nothing dynamic. We asked ourselves: what better way to practice than by playing? A game where every generation can have fun while practicing, because learning a language is a kind of magic. It turns us into bilingual wizards of knowledge.

Another partner already speaks English, but needs to reinforce it with vocabulary beyond the workplace. What better way than playing, and defeating guilds with the magic of English?

The pixel-art RPGs we grew up loving did the rest. Calice is our way of making learning English in Over the world feel like an adventure, not a worksheet.

What it does

Calice ("El Sendero del Héroe" / "The Hero's Path") is an RPG for Spanish-speaking English learners for now, playable anonymously from the very first tap, with no signup wall between a new player and the game. You pick one of 4 archetypes divided by gnere, choose your look, name your own hero, join a starting guild, and pick a spirit companion. Then you walk into Verdant Crest, Calice's first world (CEFR A1), and fight its 4 elemental dark guilds in any order you like.

Every fight is graded by a real skill, not a hit-point bar:

  • Speaking: a 60-90 second voice call with an AI tutor, graded from the transcript
  • Writing: free-text answers scored against a CEFR rubric
  • Reading: comprehension, cloze and ordering
  • Listening: audio plus questions

Winning a wave unlocks a turn-based duel with a minion; beating all 4 minions of a guild unlocks its boss, who mixes all 4 topics at once. Bosses drop a gem and a new spell (max 2 equipped at a time), and XP maps to simulate a Cambridge CEFR scale, so the level is the learner's actual level. Players also earn Runas, an in-game currency, just by playing or by watching optional reward videos, and can spend them on skins, spells and items instead of only waiting to level up. Nothing purchasable ever changes an assessment, a score, or a exam result, only how fast you get content you would unlock anyway.

How we built it

Flutter and the Flame game engine (with Bonfire) power an iOS and Android client, with Supabase as the backend. AI helps grade Speaking and Writing and generate practice questions, while Reading and Listening stay rule-based. Every world, guild and hero is drawn and designed with the same care we grew up wanting from the RPGs we loved.

Challenges we ran into

The hardest constraint was architectural, not artistic: cosmetic monetization has zero access to assessment results, so nothing a player can buy can ever change whether an answer was actually right. We were also deliberate about where AI is used, keeping it fast and affordable rather than everywhere. And building a real RPG world, with four elemental guilds that each have their own identity, around a rigorous CEFR framework meant every piece of art and every line of dialogue had to serve the story and the lesson at once, never just one or the other.

Accomplishments that we're proud of

A fully walkable World 1 (A1), start to finish: an explorable region with 4 visually distinct elemental guilds (fire, water, earth, wind, each with its own tileset, palette and enemy cast), five random wave-then-duel combat loop, full hero customization, a spirit companion narrating the whole thing, and a closing boss and story beat. It is playable anonymously, with no account required to try it.

What we learned

We learned that people practice a language far more when there is a story worth coming back to, and that keeping what is graded completely separate from what is sold is what makes a learning game trustworthy. We also learned that AI works best when it is used sparingly, exactly where it helps the learner.

What's next for Calice

Next, we want everyone to become the Wizard King: to climb their English level from A1 to A2, B1 and B2 by defeating dark bosses, casting spells and learning English. Worlds 2 through 4 will follow the same guild structure, alongside RevenueCat-powered in-app purchases (skins, spirit companions and Runas) and push notifications.

Built With

  • android
  • audioplayers
  • bonfire
  • dart
  • deno
  • edge-function
  • english
  • flame
  • fluter-tts
  • flutter
  • freezed
  • gemini
  • github-actions
  • json-serializable
  • kotlin
  • pixelart
  • postgresql
  • purchases-flutter
  • revenuecat
  • rive
  • riverpod
  • rpg
  • shared-preferences
  • supabase
  • tiled
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